Likely a change. I've seen a couple 18~55's without the lock button, on Ebay for sale. Figured if I was going to replace the lens it may as well be with one that adds a bit more focal length overlap. It's a larger barrel diameter and length but that doesn't seem to bother her. No VR with it but it is AF-S, so likely an older, 'transition' version. Got it used, from Ebay. Her long zoom is a 55~200 AF-S. Must say I've not been disappointed with the used optics I've found on there (yet). Even one from Japan: 70~300 AF-S with VR. That one looks and functions like new. Well packaged and even came wrapped in a Japanese newspaper's sports page!
I'm fairly well set with lenses now; 18~140 AF-S VR, the two primes; 50 1.4 and 35 1.8 both AF-S. Only other one I'm likely to go after would be a "nice-to-have" 40mm Micro. But I can use the Vivitar Ai-S 90mm 2.5 or my 24mm Micro Ai-S in manual for any macro stuff for now.
The only pulse motor one is a 10~20mm, but it hardly matters with a wide-angle like that and we're not doing any MoPic stuff anyway.